Fatal Accident. — As the Columbia Fire Company was on its way last night to the fire upon Seventh street, a lamentable accident occurred, which occasioned the almost instant death of Mr. Benjamin Greenup, a young man well known and much respected in this community. It seems that in coming from the engine house to Pennsylvania avenue, the most active men are usually selected to guide the engine down the hill, which is very steep, and it is as much as a swift runner can do to keep in front of the apparatus. Last night, we learn that the speed of the engine was so great, that it was necessary to check it by changing the direction. In doing this, Mr. Greenup was caught between the tongue or guiding-pole of the apparatus and a lamp post, and so injured that he died in a few minutes.